Blow molding apparatus

ABSTRACT

Cold parisons are conveyed through an oven for heating and then stretched and blown in a mould. A transfer assembly engages the upper end of each heated parison, removes it from the oven, and swings it into a mould and then rises to stretch the parison as a threading die holds the lower end thereof. The mould then closes and air is injected to form the bottle, after which the mould opens and the finished bottle is removed.

United States Patent [1 1 Moore Oct. 16, 1973 BLOW MOLDING APPARATUS[76] Inventor: Lawrence A. Moore, 13-8 16 Valley View Apartments. Kingof Prussia, Pa. 19406 [22] Filed: July 28, 1972 [21] Appl. No.: 276,071

Related US. Application Data [63] Continuation of Ser. No. 3,003, Jan.15, 1970.

3,415,915 12/1968 LeCluyse et a1. 425/409 X 3,013,301 12/1961 Lang425/301 X 3,032,809 5/1962 Willard 425/326 B 3,211,815 9/1965 Cordialeet a1 425/155 X 3,357,043 12/1967 Doucet 425/444 3,324,507 6/1967 Arlo425/392 X 3,651,186 3/1972 Hall 264/94 3,507,005 4/1970 Wiley et al..-264/94 X Primary Examiner-H. A. Kilby, Jr. Att0rney-Lars0n, Taylor andHinds [57] ABSTRACT Cold parisons are conveyed through an oven forheating and then stretched and blown in a mould. A transfer assemblyengages the upper end of each heated parison, removes it from the oven,and swings it into a mould and then rises to stretch the parison as athreading die holds the lower end thereof. The mould then closes and airis injected to form'the bottle, after which the mould opens and thefinished bottle is removed.

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sum 13 or 13 6 SEC CYL O 7 SEC. CYL. O

8 SEC. CYL. 0

DOWN

PICKER TRANSFER ARM PICKER FINGER COOLING FINGER THREAD TOGGLE ARMS PLUG

MOLD

UP STOP BLOW AIR EJECT AiR TUBE BOTTLE REMOVAL SCRAP O 40 80 I20 I60 200240 280 320 360 DEGREES OF CYCLE F/G.16

BLOW MOLDING APPARATUS This is a continuation of application Ser. No.3,003 filed Jan. 15, 1970.

BACKGROUND OF THE INVENTION This invention relates to blow moulding, andin particular it relates to a new and improved method and apparatus forheating and blow moulding cold parisons to form containers such asbottles and the like.

Numerous products such as foods, liquid soaps, etc. are now packaged andsold in non-breakable containe'rs, referred to generally as plasticbottles. These containers, which are commonly made from a polyolefinsuch as polypropylene are normally manufactured, inter alia, byextruding the material into an elongated endless hollow tube. Cut piecesof the tube, referred to as parisons, are used to form the said plasticbottles by blow moulding techniques. Although numerous differentmaterials may be used, for convenience, this specification will referspecifically to polypropylene.

Since the parisons must be hot when they are formed into bottles, theoriginal technique was to take the parisons, as soon as they were formedby the extrusion apparatus, and while they were still hot, and totransfer them directly to the blow moulding apparatus whereat they werestretched and mouled into the desired shape. However, it has been foundundesirable to necessarily link together the process of forming theparisons and the process of forming bottles from the parisons. To thecontrary, it has been found more desirable to separate these twofunctions. The parisons can then be formed into bottles at a later timeor they can be sold to others who may have facilities for formingbottles from parisons but who may not'have facilities for initiallyforming the polypropylene parisons.

The separation of these two functions of course means that the processof forming the bottles must start with cold parisons which must first beheated. Consequently, this technique has become known as the coldparison technique.

In known cold parison techniques, the parisons are first conveyedthrough an oven with the tubular parisons upright on vertical pins. At amoulding station, a gripper grips the bottom of a given parison andlifts the same upwardly until the top is engaged by a head platen whichholds the parison and forms the threads and the neck of the bottle atthe top thereof as the gripper moves downwardly to stretch the parison,after which the mould is closed and air is blown into the mould fromabove through the head platen ,to form the bottle. The mould is thenopened and the finished bottle is ejected from the moulding station.

While this known technique has proved relatively successful, it suffersfrom at least the following disadvantages. First, the apparatus forcarrying out this technique is quite complicated. Secondly, theoperation of this technique required a rather high cycle time of 12seconds per bottle in mass production (for a given moulding station).

Thus, there exists a need for an improved blow moulding method andapparatus which is more simplified than apparatus known heretofore, andwhich will permit more rapid, and hence more efficient production ofbottles from cold parisons.

SUMMARY OF THE INVENTION Thus, it is a purpose of this invention toprovide a new and improved blow moulding method and apparatus forrapidly converting cold parisons into containers such as bottles in amanner which is more simplified and economical than previously knowntechniques.

The purpose of the invention is achieved by providing an arrangementwherein the various stages of operation are quite simplified in and ofthemselves and are arranged to cooperate with each of the other stagessuch that the parisons are carried thorugh the various stages in a mostrapid and efficient manner.

In a preferred arrangement of the invention, the parisons are first fedinto and conveyed through an oven which includes new and advantageousfeatures for assuring prompt and uniform heating of the parisons. Theoven is so arranged that when a given parison has reached the properforming temperature, it arrives at a discharge station.

The mould is located at a mould station adjacent the oven in thevicinity of the said discharge station thereof. A threadforming mean ismounted at one end of the mould and is adapted to engage one end,preferably the lower end, of a heated parison to form the neck and thethreads of the bottle therefrom and to hold that end of the parison asthe other end is moved during a stretching procedure immediately priorto the closing of the mold which is of course followed by the injectionof pressurized air into the bottle while the. mould is closed to shapethebottle therein. After the bottle has been formed, the mould is openedand air may be injected again, this time to move the finished bottleinto the flared open end of a tube through which the finished bottle maybe removed.

An important feature of the present invention includes means forhandling the parison between the discharge station of the oven and thethread forming means at the moulding station. This means comprises atransfer assembly which includes a generally vertical post attached tothe base of the apparatus, a generally horizontal transfer arm extendingoutwardly from the post and a generally vertical picker arm extendingdownwardly from the outer end of the transfer arm. The picker armincludes jaws for engaging and holding parisons. The transfer arm-pickerarm assembly is movable horizontally preferably for being turned in acurved path, and also vertically.

In the operation of the apparatus, the transfer armpicker arm assemblyis lowered into the oven at the discharge station such that the pickerarm jaws grab the top of a properly heated parison. The transferarmpicker arm assembly then rises out of the oven and turns until itreaches a point over the thread-forming means whereat the parison islowered such that the lower end of the parison may be engaged by thesaid thread forming means. This latter means forms the opening whichwill later comprise the opening of the bottle (for example, this openingmay include a neck and/or threads) and this means will continue to holdthe bottom of the parison as the transfer arm-picker arm assembly, while.still holding the upper end of the parison, moves upwardly to stretchthe parison. After stretching, the mould is closed and air is injectedthrough the said opening of the bottle to shape the bottle within themould. As the bottle is being formed in the mould, the transferarm-picker arm assembly swings back to its original position over thedischarge station of the oven. Conveniently, a scrap chute can beprovided between the discharge station and the mould station whereat thetransfer arm-picker arm assembly may stop momentarily and open torelease the scrap upper portion of the parison.

After the moulding step, the mould is opened and additional air may beinjected into the bottle. However, with the mould open, this additionalair may throw the 'bottle upwardly. A flared end tube is convenientlyplaced above the mould for receiving the upwardly hurled finished bottleand removing the same from the moulding apparatus.

With this preferred arrangement of the invention, cycle time for a givenmoulding station may be substantially reduced since wasted motion issubstantially reduced, if not eliminated. For example, the present cycletime is 7 to 8 seconds per bottle and it is believed that this'can bereduced to 6 seconds which includes 4 seconds with the mould closed.This is made possible by the interrelationship of the various parts ofthe apparatus. For example, during the 4 seconds that the mould isclosed, the transfer arm-picker arm assembly can discharge the scrap endof the parison, pick up a new parison and swing this new parison over toa point just adjacent to the mould. The remaining 2 seconds during themould open position would be required merely to eject the finishedbottle, lower the new parison to the threading and holding means and tostretch the parison by raising the transfer arm-picker arm assembly.

The present invention includes many new and advantageous features whichwill be explained in greater detail below.

Thus, it is an object of this invention to provide a new and improvedmethod and apparatus for blow moulding containers from cold parisons.

It is another object of this invention to provide a rapid but yet asimplified method and apparatus for forming containers from coldparisons by blow moulding techniques.

It is another object of this invention to provide a method and apparatusincluding an oven, a. transfer arm-picker arm assembly, a moulding meansand a thread forming and holding means, which means cooperate with eachother in such a manner as to permit a substantial reduction in cycletime per container in the formation of containers in the cold parisonblow moulding technique. 7

Another object of this invention is to provide a new and improved ovenfor efficiently and uniformly heating a large number of parisons.

Other objects and advantages of the present invention will becomeapparent from the detailed description to follow together with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is an enlarged plan view of anoven, which view is similar to FIG. 2 but with the top of the ovenremoved.

FIG. 5 is an enlarged side view of the oven, which view is similar toFIG. 1 but wherein the side plate has been removed.

FIG. 6 is an enlarged end elevation view of the oven, as viewed from therighthand side of FIG. 1.

FIG. 7 is a cross-sectional view of the oven taken along line 7-7 ofFIGS. 4 and 5.

FIG. 8 illustrates the transfer arm-picker arm assembly and is takenalong line 8-8 of FIG. 2.

FIG. 9 is a sectional view taken along line 99 of FIG. 8.

FIG. 10 is a sectional view taken along line 1010 of FIG. 8.

FIG. 11 is an elevational view of a mould closing clamp and is takenalong line l111 of FIG. 2.

FIG. 12 is a view similar to FIG. 11 but showing the elements when themould is in the closed position.

FIG. 13 is a plan view of the thread forming and hold ing assembly andis taken in the direction of the arrow A in FIG. 1.

FIG. 14 is a cross-sectional view taken along line l4l4 of FIG. 13 andshowing a bottle in the mold.

FIG. 15 is a cross-sectional view taken along line 15-15 of FIG. 13showing a bottle in the mold.

FIG. 16 is a graph illustrating the operation of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to thedrawings, like elements are represented by like numerals throughout theseveral views.

FIGS. 1 and 2 illustrate the overall apparatus of the present invention.A parison treatment apparatus 10 .ing 16 formed in the top of the oven.A transfer armpicke r arm assembly 17 is located in the vicinity of thisdischarge opening 16 and is adapted to enter the oven to grasp andremove a heated parison and to move upwardly and then horizontally aboveopposing halves 19 of a mould. Locatedjust beneath the space between thetwo mould halves 19 is a threading and holding assembly 18. The assembly17 lowers the parison between the open mould halves 19 until the lowerend of the parison is grasped and held by the assembly 18. The transferarm and picker arm assembly 17 then rises upwardly, stretching theparison after which the mould halves 19 close. The assembly 17 thenmoves back to its original position over the opening 16, meanwhiledropping the scrap upper piece of the parison into the chute 20. Afterthe container has been formed in the mould, the mould halves 19 separateand the finished container is removed through discharge tube 21;

The elements l7 through 21 are mounted on a raised base 22 which islocated to the left of the oven I1 (as viewed in FIGS. 1 and 2).

The various portions of the apparatus, which have been described onlygenerally with respect to FIGS. 1 and 2, will now be described inspecific detail with reference to FIGS. 3 through 15.

The parison feeder 12 is shown in detail in FIG. 3 and details are alsoshown in FIGS. 1 and 2.

The parison feeder 12 includes a generally rectangular hopper 30 havinga bottom 36 for receiving tubular parisons 35 (see FIG. 3). The bottom36 is open at the middle. Below this bottom 36, and extending upwardlythrough the said middle opening, is a rotor 31 having a pair ofelongated grooves 32, each groove of sufficient depth to receive atubular parison therein. This rotor 31 is turned at a speed in time withthe oven conveyor chain 50 by a right angle gear unit 33 for deliveringparisons 35 to a vertical chute 34. Each groove 32 thus receives aparison at its upper position and drops it into the chute 34 at itslowermost position. The chute 34 is so curved that a parison droppingdown this chute turns 90 and becomes vertically oriented after which theparison is received in a vertical guide tube 40 which delivers theparison onto the conveyor in the oven 11. For efficient operation, it isapparent that a parison 35 should drop into a groove 32 each time that agroove 32 reaches its uppermost position. Such efficiency of operationrequires that the parisons be laid neatly across the hopper 30. However,to assure this arrangement, the width of the hopper 30 (as in FIG. 3)should be approximately the same as the length of the tubular parisons.However, it is of course apparent that the hopper 30 must be capable ofdelivering parisons of different sizes. Therefore, to render the hopperadjustable, a plate 37 extends across the hopper and the position ofthis plate across the hopper 30 (as viewed in FIG. 3) is determined byadjusting arms 38 having notches 39 formed in the bottom thereof forsecuring the plate 37 ata given position.

The purpose of the oven 11 is to heat the parisons slowly and uniformly.In one examplary embodiment of the invention, the oven is capable ofcarrying 271 parisons, and when heating parisons of polypropylene havingan outside diameter of 1.033 inches and a length of from 5 to 6 inches,the oven will be heated to a temperature of approximately 326 Fahrenheitand each parison will travel in the oven for 36 minutes and will becomeheated to a temperature of approximately 318 Fahrenheit. It is to beunderstood however that the invention is in no way limited to thisexemplary data.

The parisons are received from the parison feeder 12 into the tube 40(see the upper righthand corner of FIG. 4) from which they fall into oneof the 271 pins carried by the conveyor chain 50. This chain 50 with theparisons traveling thereon moves by sprockets 51 through 58,respectively. The parisons are removed at the discharge station 16 whichis located just above the sprocket 58. The empty pins then travel fromsprocket 58 by sprocket 59 and sprocket 60 where they receive a newparison. Although not illustrated in the drawing, it will, beappreciated that the parison feeder 12 could be provided above thesprocket 59 instead of the sprocket 60. This would permit each parisonto remain in the oven a longer period of time, namely the time requiredto travel between the sprockets 59 and 60. However, this additional timeis not always required and hence on numerous occasions it is quitepractical to have the feeder 12 located as shown in the drawings.However, this also illustrates the flexibility of the present invention.Assuming that the oven is constructed with a guide tube 40 and itsassociated parison receiving apparatus at each of sprockets 59 and 60,then to move the feeding position, it is only necessary to unbolt thefeeder 12 from the illustrated position and move it to the position overthe sprocket 59.

A drive shaft 49, which may be operated by any suitable power means,turns the sprocket 58 to drive the chain conveyor 50.-

A system of chain tracks 61 extends through the oven and is visible inFIG. 4. t

A portion of the chain 50 is shown in detail in the middle of FIG. 5.Four of the 271 parison pins 62 are shown here connected to the chain50. All other parison pins are connected in the same manner. Also shownin FIG. 5 are the details of the guide tube 40. Actually, a pair ofguide tubes 40 is provided on for rotation about a loading wheel 41.

As noted above, the oven is constructed in order to provide a steady anduniform flow of heated air through the oven. To accomplish this, theoven includes a main inlet duct 63 which receives the heated air fromheater 13 and which extends the entire length of the oven. This duct isshown in cross-section in FIG. 7. The plate 63 which forms the top ofduct 63 has a plurality of apertures therein. Immediately above the duct63 is a second duct 64 which is much smaller in height than 63. The topof duct 64 is formed by a plate 64 which includes a plurality ofapertures which are offset from the apertures in plate 63'. Thisprovides a high pressure drop and prevents jets of air from flowingdirectly from the inlet duct 63 through to the open space above theplate 64. Thus, uniform heat distribution is assured, at least in part,by the high pressure drop of the incoming air through the plate 63.Above these ducts 63 and 64 there is provided a set of vertical,preferably corrugated baffle plates 65 which extend for the full lengthof the oven and which are connected to the plates 63 and 64 by suitablerods 66. These plates assure even upward movement of the heated air andprevent cross-flow of the rising air between the rows of conveyor 50.The baffles also assure equal radiation from all directions as theparisons pass through the oven. In this way, the cold wall effect iseliminated. Spaced slightly above the plates 65 is an outlet duct 67which also extends for the full length of the oven and which is visiblein cross-section in FIG. 7. This duct is of course apertured on itsbottom side for receiving the upwardly flowing air. From the duct 67 theair travels downwardly through the return duct 68 to the inlet duct 69of the fan 70 which in turn is operated by a motor 73 for blowing thereturned heated airby a air flow valve 71 through the air heater l3 andthen through a duct 72 to the said inlet duct 63. For viewing andinspecting the inlet end of the oven there is provided a door 74 mountedon hinges 76 and having a handle 77. The door also includes a plexiglassviewing window 75.

FIGS. 8 through 10 illustrate the transfer arm-picker arm assembly 17 ingreater detail. This assemblyincludes a transfer arm 80 connected bypins 81 and a rectangular mounting block 82 to a spindle 83 which istumabl-e about its axis 84. The spindle 83 is also capable of slidingvertically parallel to its axis, and thereby raising and lowering itstransfer arm 80. The spindle 83 is supported for sliding movement inbearings 85. Further, the spindle 83 is splined and includes grooves 86running for the full length of the spindle. Rolling balls 87 of a ballbearing spline 88 extend into the grooves 86. fixed to the spline 88 formovement therewith is a further tube 89. The elements 88 and 89, whichare fixed together, are separated from an outer tube 90 by bearings 93and 94. The outer tube 96 is fixed by means formounting plate 95 to theraised main frame 22. However, 88 and 89 are turntable within this outertube 90. Thus, it can be seen that any turning movement applied to thetube 89 will be applied through the ball bearing spline 88 and the balls87 to the spindle 83, and

' this will be the case regardless of the vertical position of spindle83 since the grooves 86 therein extend for the full length of thespindle 83. Referring to FIG. 9, it can be seen that the outer tube 90includes a set of opposed openings91 through which extend lugs 92 (oneof which is shown) which are fixed to 89. Thus, by turning lug 92 aboutaxis 84, one accomplishes turning movement of the spindle 83 and hencealso of the transfer arm 80.

Vertical movement of this spindle 83 is carried out by means of ahydraulic cylinder 96 fixed to the lower end thereof. The hydrauliccylinder unit is conventional and thus is not shown in detail. It issufficient to note that the element 96 is connected through the flangeelement 97 and the disc 98 and through the bolt 99 to the bottom ofshaft 83 for movement therewith.

As is evident from FIG. 8, the spindle is shown in its lowermostposition whereat the transfer arm 80 lies just above the top of the oven1 1. At this point an extension 80 of the transfer arm 80 abuts anadjustable down stop bolt 105 which has a locking nut mounted thereonand which is supported by a bracket 107 which is in turn fixed to theouter tube 90. Upward movement of the spindle 83, and hence also of thetransfer arm 80 is limited by an up stop assembly 108 which is mountedon support columns 115 above the transfer arm 80. Specifically, upwardmovement of transfer arm 80 is limited by engagement with a stop nut110. For reasons to be explained in greated detail below, the verticalposition of this stop nut 110 must be changed to different positionsduring normal operation of each cycle of the apparatus. Therefore,assembly 108 includes a vertically movable pneumatic cylinder 109slidable relative to a piston 111 which is in turn connected through aflange element 112 by means of nuts and bolts to the support columns115. Stop Nut 110 is fixed to cylinder 109 for movement therewith. Alowered position of 109 and 110 is shown in dotted lines in FIG. 8.Movement of the pneumatic cylinder 109 will be synchronized with theother elements of the overall apparatus so that the element 110 assumesthe correct position during the various stages of the cycle,.as will beexplained in greater detail below.

Also shown in FIG. 8 is the picker arm which includes an outer housing120 which is fixed with respect to the transfer arm 80 and includes atthe lower end thereof a bearing 121 fixed to the housing 120. Thehousing includes an enlarged lower portion 122. A central piston 123extends for the full length of the housing 120 and includes an enlargedhead at its upper end which extends across the entire cross-section ofthe interior of housing 120. A spring 124 urges the head of 123 upwardlywhile downward movement thereof is provided by pneumatic fluid enteringa passageway 125 in a head member fixed to the housing 120.

At its lower end, piston 123 is connected by a pivot connection 126 to apair of upper links 127 which are in turn connected at pivot connections128 to lower links 129. These lower links are turned about pivot pins130 which are connected to the housing portion 122 and these lower links129 include at their lower ends picker jaws 131 which may be movedinwardly and outwardly with respect to each other. Thus, it can be seendownward movement of 123 will cause the jaws 131 to move towards eachother to grasp and hold an element such as a parison locatedtherebetween. Similarly, upward movement, of the element 123, which willoccur when the pressure is released from line 125 and the spring 124urges the element 123 upwardly, will cause the jaws 131 to separate fromeach other.

FIGS. 11 and 12 illustrate the means for opening and closing the mouldhalves 19. This apparatus includes a clamping frame having a pair ofguide rails 141 ex tending completely across the frame 140 and supportedin the center by support 153. Mounted on these guide rails are twocarriages 142, each of which is rigidly connected by means of an arm 154(see FIGS. 1 and 2) to one of the mould halves 19.

FIGS. 11 and 12 illustrate the same view of the same elements exceptthat in FIG. 11 the mould halves 19 are separated (as they are in FIGS.1 and 2) while FIG. 12 illustrates the same elements in the movedposition with the mould halves 19 closed together.

The two carriages 142 are connected together by .means of curved togglelevers 144 which are connected at their outer ends at pivot connections143 to their respective carriages 142 and are connected at their innerend at pivot connections 145 to a central driving disc 144 which isrotated back and forth by a drive motor 147 (see FIG. 2). An abutmentfixed to the frame 140 extends downwardly and includes first and secondabutment edges 151 and 152. In the open position, as shown in FIG. 11, afirst abutment surface 148 on the disc 146 engages surface 151 andthereby limits rotation of the disc 146 in the counterclockwisedirection. This represents the fully separated position of the carriages142 and thus of the mould halves 19. To close the mould, that is to movethe elements to the position shown in FIG. 12, the disc 146 is turnedclockwise until the edge 149 engages surface 152. Inward movement of thecarriage 142 is stopped by the mould faces making contact with eachother.

In operation, very high pressures are exerted at the interior of themould where the container is being formed. The curved overlapping togglearrangement shown in FIGS. 11 and 12 is particularly advantageous forthis application since it requires a greater force to separate the twocurved, overlapping toggles 144 than would be the case if straighttoggle levers were used. For example, if in face the straight togglelevers were I used, then any force tending to separate the mould halves19 would tend to act in the direction of movement of the straight leversthemselves since the force would normally act in a direction parallel tothe path which the levers follow when they separate. However, with thepresent arrangement any force tending to force the mould halves 19 wouldtend to pull the pivot point 145 in a horizontal direction. But incontrast with straight levers, in the present case the ends of thecurved levers at the disc 146 must travel not horizontally but outwardly(up or down) and then horizontally. Thus, when the mould is closed, onlya portion of the mould halves 19.

The drive motor 147 may be a Rotac" unit made by Excello Corporation andthe toggle mechanism can withstand a separating force of l0,000 pounds.

FIGS. 13 through illustrate in detail the thread forming means 18.

First, in the upper portion of FIG. 15 there is shown a container, inthis case a bottle 159 of the type which might be formed by the presentapparatus from the tubular parison, for example as shown in FIG. 3.

Referring now generally to FIGS. 13 through 15, the assembly 18 includesa thread assembly frame 160 which is mounted directly on the frame 22 bysuitable bolts or the like. As best shown in FIG. 13, the thread formingmeans includes a pair of arms 161 and 162 rotatable about the axis 163,this axis also being shown clearly in FIG. 15. A thread die 164 isconnected to a semi-circular recess formed in the arm 161 and held thereby a bolt 166 which passes completely through the arm 161. This bolt isshown in both FIG. 13 and FIG. 14. Similarly, a mating thread die ismounted in a semi-circular recess formed in the arm 162 and held thereby a similar bolt 167. The two arms 161 and 162 are urged together andseparated by a mechanism identical to that used for controlling theclosing andopening of the mould halves 19. In the thread assembly, thismeans includes a pair of toggle levers 168 and 169, the former attachedto arm 161 at pivot 170 and the latter attached to arm 162 at pivot 172.Beneath the levers 168 and 169 is a rotating disc 174 which is similarto the disc 146 in FIGS. 11 and 12. This disc has a pair of abutmentedges 175 and 175' which limit the clockwise and counterclockwiserotational movement of the disc 174, respectively, by engagement with anabutment member 176 which is similar to the abutment member 150 in FIGS.11 and 12. Lever 168 is connected to the disc 174 at pivot connection171 and lever 169 is connected to the disc 174 at pivot connection 173.In the same manner as in FIGS. 11 and 12, only a small component of theforce tending to separate the arms 161 and 162 is effective to urgeseparation of the levers 168 and 169. Turning movement of disc 174 isprovided by a motor 177 (see FIG. 15).

Also included in the assembly 18 is a vertically movable plus member anda means for introducing air under pressure into the container 159 whichis being formed. Referring specifically to FIGS. 14 and 15, thisapparatus includes a plug 180 which is movable vertically to the raisedposition as shown in solid lines in FIGS. 14 and 15 to a loweredposition as shown in dotted lines in FIG. 14. This plug is connected toan adaptor member 181 and is surrounded by a bushing 183 which slidinglysupports the plug 180 and a wear plug 182, the latter being held firmlywithin the frame 160. An air line 184 delivers pressurized air to apassage 185 in the adaptor 181 which in turn delivers air to a pas sage186 in the plug 180. At the appropriate times, as will be explained indetail below, air under pressure is introduced thorugh this line 184 andhence into the bottle 159.

Vertical movement of the plug 180 is provided by a double actinghydraulic cylinder and piston unit 188 which is supplied at itsrespective ends with fluid under pressure through lines 189 and 190.This cylinder 188 is connected to the adaptor 181 through a suitable rod187. The lowered position of the plug and its associated elements isalso illustrated by the lowered dotted line position of element 181 inFIG. 14.

After the mould halves 19 have been separated and the bottle has beencompletely formed, the arms 161 and 162 separate and the bottle isejected by being urged upwardly by air passing through the line 186 andinto the bottle. This bottle, thus thrown upwardly is received andremoved by the finished bottle discharging unit 21, as shown in FIGS. 1and 2. When the mould separates, the flexible tube 203, and particularlythe flared end 207 thereof is positioned directly over the bottle sothat when the bottle is thrown upwardly it is received within this tubethrough which it is drawn outwardly to a receiving station. The lowerend of tube 203 is held by a tube carrying arm 201 which has fixedthereto a downwardly extending pin 202 which is received loosely in ahollow support tube 200 which is fixed to the base 22. Thus; the arm 20]is permitted to rotate about a vertical axis through the tube 200. Thisarm'201 is normally urged to the position over the mould by means of aspring 206 acting between a first fixed element 204 connected to thetube 200 and a second flanged element 205 connected to the arm 201.However, this arm 201 is also connected through a suitable mechanicalconnection such as a cam or the like to the transfer arm-picker armassembly 17 so that whenever the assembly 17 moves into the area abovethe mould 19, the arm 201 automatically swings counterclockwise (asviewed in FIG. 2) from the position over the mould 19 in a directionoutwardly away from the mould 19 as shown by the arrowB in FIG. 2.

The operation of the apparatus and also the method of the invention havebeen described in part during the discussion of the various componentsof the apparatus. However, for further clarity, a summary of the methodand operation of the invention will now follow. For a furtherunderstanding of this operation, reference is made also to FIG. 16 whichshows the interrelated movements of the numerous components of theinvention for three'different time cycles, namely a 6 second cycle, a 7second cycle and an 8 second cycle.

Assuming that it is desired to convert tubular parisons 35 into bottles159, the parisons are first stacked neatly in the hopper 30 of thefeeding device 12 with the assistance of plate 37. These parisons arefed by means of grooves 32 in the rotor 31. If the speed of conveyorchain 50 is such that rotor 31 rotates at a speed of four revolutionsper minute, and assuming the rotor 31 includes two grooves 32, this ofcourse means that eight parisons 35 will be delivered into the oven 11through chute 35 per minute, that is, one parison would be introducedevery 7.5 seconds. If the cycle time is to be reduced, the conveyorchain50, and hence also the rotor 31 would be speeded' up accordingly.In the oven 1 1, the parisons are received on pins 62, on which theytravel along conveyor 50 through the baffle system becoming uniformlyheated. The number of parisons held by the oven is selected to suit.boththe heating cycle and the forming cycle. For example, for a heating timeof 36 minutes and a cycle time of 8 bottles per minute, the oven willhold 288 parisons which equals 36 minutes times, 8 parisons per minute.Similarly, for 40 minutes and I0 parisons per minute the oven will hold400 parisons, etc. The importance of uniform heating of the parisonscannot be overemphasized. If the parison is not heated to the sametemperature uniformly along its length, then it will not be stretcheduniformly at a later point in the operation and hence the resultantbottle 159 may be defective in that it may vary in thickness by anunacceptable amount from one end to the other. Although the conveyor 50could possibly be indexed, in a preferred embodiment of the invention itmoves continually through its illustrated path. To compensate for this,the transfer arm-picker arm assembly 17 is constructed so that when thelower end of the picker arm extends into the opening 16 at the dischargestation, it moves slightly in its curved path about axis 84 as the jaws31 grip a parison.

As soon as a parison has been firmly grasped by jaws 131, the cylinder96 is actuated to raise the spindle 83 thereby raising the picker armand the parison being grasped thereby. At first the picker arm stops atits raised position whereat the first parison is gripped by coolingfingers (which are not shown in detail in the present drawings) whichsimply cool the parison locally to a uniform but slightly lowertemperature. Suitable mechanical means, not shown, then actuate the lugs92 to turn the tubular elements 88 and 89, and hence also the spindle 83and the transfer arm 80 until the parison is directly over the plug 180and the space between the open, that is spaced apart arms 161 and 162 ofthe threading assembly. As explained above, this movement of thetransfer arm 80 mechanically assures that the tube 203 has been movedoutwardly away from its position over the threading means 18.

At this time, the cylinder 96 is again actuated to lower the spindle 83until the bottom of the parison being held by the jaws 131 abuts theupper end of bushing 183 between the thread dies. Motor 177 is thenactuated to close the arm 161 and 162 onto the lower end of the parison.Plug 180 is then raised. This serves several purposes. First, itpositively positions the bottom of the parison. Secondly, it positivelysizes the inside of the threaded area. Thirdly, it pushes material intothe thread die cavities and itswedges the material in the lip area andpushes material up into the shoulder area. Another function of thethread dye assembly is to firmly hold the bottom of the parison as thejaws 131 are raised to stretch the parison. FIG. 15 illustrates indotted lines the parison 35 after it has been stretched. Note the lengthof the parison 35a in FIG. 15 in comparison to the length of parison 35in FIG. 3 During this stretching procedure, the jaws 131 should not bepermitted to rise to their maximum height at which they were locatedwhen they carried the parison from the oven to the area of the mould.Thus, the upward movement of the arm 80 and hence the picker arm and thejaws13l must be limited. For this purpose the stop out 110 shown in FIG.8 is lowered as the stretching procedure takes place. Thus, upwardmovement of the jaws 131 during stretching is limited by engagement ofthe arm 80 with the stop nut 1 10 in its lowered position 110 as shownin FIG. 8.

After the parisons have been stretched, motor 147 is operated to closethe two mould halves 19. At a level as shown in FIG. 15 corresponding towhat will be the bottom of the bottle (that is the closed upper end asshown in FIG. 15) the parison is cut by the mould. At this point twoevents occur concurrently. First, the stop nut 110 is raised to itsuppermost position permitting maximum rise of the transfer arm-pickerarm assembly so that the scrap portion of the parison, that is theportion above the cut, is moved upwardly above the mould. The arrn thenswings counterclockwise (as viewed in FIG. 2) as the transfer arm againreturns to its position over the discharge opening 16 of the oven 1 1.However, en route to this position the transfer arm 80 moves over thechute 20 whereat the jaws 131 are separated so that the scrap portion ispermitted to run down the chute 20 into a suitable recepticle. Thetransfer arm 80 then continues its travel to the oven to grasp anotherparison after which it commences its return to the mould. Meanwhile,concurrently with above described movement of the arm 80, air underpressure is introduced through line 184 and hence through passages and186 into the closed portion of the parison remaining in the mould. Ofcourse in a conventional manner the faces of mould halves 19 are of theshape of the bottle 159 to be formed so that the air under pressurecauses the hot parison to move against the walls of the cavities formedin mould halves 19, thereby forming and shaping the bottle. 159.Meanwhile, since the transfer arm 80 has moved back to its position overthe oven 11, the arm 201 has been permitted, under the influence of itsspring 206, to move back to the position over the mould halves 19. Motor147 is now operated to separate the mould halves and motor 177 isoperated to separate the arms 161 and 162. Air is again introduced intothe passage 184, and hence 185 and 186 and into the bottle 159. However,this time since the mould is open and the arms 16] and 162 areseparated, this air causes the bottle 159 to be thrown upwardly whereatit is received in and carried away through the tube 203.

One advantageof the present invention is the simplicity which resultsfrom the arrangement of the various components of the assembly. Asexplained above, the various components cooperate with each other in anextremely advantageous manner in order to carry out the purposes of theinvention. Notwithstanding this, however, the various components areindividually mounted on a common base such that any one of the majorcomponents can be dismantled and removed from the apparatus forservicing or repair without disturbing the other components of theassembly. Stated differently, the assembly is of a modular construction,each of the major components of the assembly comprising one modulethereof. For example, the feeding means 12 can be removed from the topof the oven and located at a different position. Further, any one of thetransfer arm-picker arm assembly 17, the threading assembly 18, themould frame 140, the scrap discharge chute 20 or the finished bottledischarge chute 21 can simply be unbolted and removed from the raisedmain base 22. Of course, it is also possible to remove the oven 11.However, in view of its size, relative to the remaining components ofthe assembly, this would not normally be practical.

As explained above, the various components of the assembly cooperatewith each other by operating in synchronism with each other to carry outthe purposes of the invention. This may be carried out, for example, byoperating'all of the various valves which control the flow of pressurefluid to the various components by means of a common rotary switchhaving a plurality of cams mounted thereon, each cam controlling adifferent valve and/or a different component of the assembly. Forexample, one cam on the rotary switch may be provided for each of thefollowing: (a) hydraulic cylinder 96 for raising and lowering thespindle 83, (b) a fur-

1. An apparatus for producing blow molded articles comprising: an ovenincluding an enclosed chamber and means for supporting tubular parisonsand passing the parisons through the chamber to heat theiR parisonsalong their lengths; a blow mold positioned in close proximity to theoven and including means for supporting a tubular parison from below andfor blow molding the tubular parison into a blow molded article; and atransfer member for transferring heated tubular parisons from the ovento the mold, said transfer member comprising, a vertical spindle movableabout and vertically along a vertical axis, a horizontal transfer armattached to the spindle and movable therewith vertically along andangularly about said axis, a gripping means attached to the transfer armfor movement therewith and extending downwardly therefrom for graspingthe top of a tubular parison, said transfer member including means formoving the transfer arm downwardly at the oven, for operating thegripping means to grasp a heated parison at the oven, for moving thetransfer arm upwardly to raise the grasped heated parison out of theoven, for moving the transfer arm horizontally about said vertical axisand for lowering the parison for supporting the bottom thereof by saidsupporting means.
 2. An apparatus according to claim 1, wherein saidtransfer member includes means for raising the transfer arm and grippingmeans and hence also raising the top end of the parison being held bythe gripping means while the lower end of the parison is being held bysaid supporting means, thereby stretching the parison.
 3. An apparatusaccording to claim 2, wherein said means for raising includes means forlimiting the upward movement of the transfer arm at a first height atwhich the gripping means is above the blow mold, and said blow moldincluding means for cutting off the top of the parison as it closed ontothe parison.
 4. An apparatus according to claim 3, said transfer memberincluding means for raising the transfer arm to a height above the saidfirst height after the parison has been cut and for moving the transferarm about said vertical axis back to the oven.
 5. An apparatus accordingto claim 4, including means for releasing the top of the tubular parisonfor movement onto a scrap chute as the transfer arm moves back to theoven.
 6. An apparatus according to claim 4, including meansinterconnecting the blow mold and the transfer member for coordinatedmovement such that during the time that the blow mold closes and forms amolded article, the transfer member moves to obtain another tubularparison from the oven.
 7. An apparatus according to claim 1, wherein thesaid blow mold includes an opeable and closeable mold, and said supportmeans includes a thread clamp means located below the mold for engagingthe lower end of a parison, whereby when the gripper means lowers theparison at the mold, the lower end of the parison is grasped and held bythe thread clamp means so that the subsequent raising of the parison bythe gripper means causes stretching of the parison.
 8. An apparatusaccording to claim 7, wherein the thread clamp means comprises a pair ofarms movable towards and away from each other, and said arms beingoperated by a rotatable member connected to the arms by a pair of curvedlevers which are connected to the rotatable member such that when thearms are in the closed position the levers overlap each other in adirection perpendicular to the direction of opening and closing movementof the arms.
 9. An apparatus according to claim 7, wherein said transfermeans includes an up stop and a down stop for respectively limitingupward and downward movement of the transfer arm, said up stopincluding, for each cycle of operation of the apparatus, at least twovertical positions, the lower of which limits upward movement of thepicker arm during stretching of the parison and the upper of whichrepresents the maximum height to which the picker arm can be raised. 10.An apparatus according to claim 7, wherein said thread clamp meansincludes a pair of thread dies and a pair of thread clamps, each clamphaving a thread die attached thereto, the two clamps being turnableabOut a common axis to close the thread dies onto the bottom of aparison.
 11. An apparatus according to claim 7, said clamp meansincluding a pair of thread dies each connected to a separate clampmember, the clamp members being movable to close the thread dies ontothe bottom of the parison, a plug movable upwardly into the bottom ofthe parison between the thread dies and including a passageway throughthe plug and means for passing a high pressure fluid through the saidpassage and into the parison.
 12. An apparatus according to claim 11,including a mold clamp means for closing the mold with the stretchedparison located therein, means for opening the mold and means forinjecting high pressure fluid through the said passageway while the moldis closed to shape the parison into a container.
 13. An apparatusaccording to claim 1, including means for injecting fluid through thepassageway after the mold has opened to eject the finished containerfrom the mold.
 14. An apparatus according to claim 1, including meansadjacent the said discharge station of the oven for contacting theparison to cool the same as the parison is removed from the oven.
 15. Anapparatus according to claim 1, wherein said mold and said transfer armoperate simultaneously such that when the mold is closed during theformation of a container, the transfer arm moves back to the oven tograsp another heated parison and starts its movement back towards themold.
 16. An apparatus according to claim 15, wherein when the moldclosed, it closes the uppermost part of the container being formed andcuts the parison, and wherein the said gripping means includes means fordropping the upper scrap part of the parison into a scrap receivingmeans as the transfer arm moves back from the mold to the oven.
 17. Anapparatus according to claim 1, wherein said oven means comprises ahousing, a conveyor in the housing for conveying said elements along aplurality of generally parallel vertical baffles between said paths, anda heated air inlet duct below the paths and an outlet duct above thepaths.
 18. An apparatus according to claim 17, wherein the conveyormoves along said back and forth path continuously, said path beingendless, and feed means for feeding parisons to the oven at one point insaid path, and means for permitting removal of heated parisons by thesaid transfer member at another point in said path.
 19. An apparatus forproducing blow molded articles comprising an oven including an enclosedhousing, means for heating the interior of the housing to heat theparisons, a conveyor means movable continuously along a path in thehousing, support means on the conveyor for supporting a plurality oftubular parisons in an upright position as they move through the oven,and a discharge station at which the tubular parisons are removed fromthe oven, a blow mold positioned in close proximity to the oven, atransfer member for transferring heated tubular parisons from the ovento the mold, said transfer member including, a vertical spindle movablevertically along a vertical axis and angularly about the vertical axisat any vertical position of the spindle, a transfer arm attached to thespindle for vertical and angular movement therewith, said transfermember including a gripping means operatively connected to the transferarm for movement therewith to grasp a tubular parison, said transfermember including means for lowering the transfer arm to a loweredposition at the oven, means for operating the gripping means to grip aparison, and means for turning the transfer member about that axis whilethe transfer arm is in a lowered position at the oven, such that thegripping means follow generally the same path as said conveyor means atthe discharge station such that the transfer member is operable to graspa heated tubular parison for transfer to the blow mold while theconveyor moves continuously along the path.
 20. An apparatus accordingto claim 19, said transfer member further including meaNs for raisingthe transfer arm with the grasped parison, for turning the transfer armhorizontally about said axis to the blow mold, and for lowering thetubular parison at the blow mold.
 21. An apparatus according to claim20, said oven conveyor being an endless conveyor, means for loadingparisons on the support means at a loading station, whereby the parisonsare heated as they travel along the endless path from the loadingstation to the discharging station.
 22. An apparatus for producing blowmolded articles comprising: an oven including means for passingelongated tubular parisons through the oven and means for heating theparisons along their lengths as they pass through the oven, a blow moldpositioned in close proximity to the oven, said blow mold includingmeans for supporting the bottoms of the tubular parisons and means forblowing air into the bottoms of the blow mold to form the tubularparisons into molded articles, a transfer member for transferring heatedtubular parisons from the oven to the blow mold, said transfer memberincluding a vertical spindle movable about and vertically along avertical axis, a horizontal transfer arm attached to the spindle andmovable therewith vertically along and angularly about said axis, agripping means attached to the transfer arm for movement therewith andextending downwardly therefrom for gripping the top of the tubularparison, said transfer member including means for moving the transferarm about said vertical axis between the oven and the blow mold forcarrying parisons from the oven to the blow mold, a hollow removal tubehaving an open end positioned above the blow mold such that when theblow mold is opened after forming a molded article and the blowing meansblows air, the molded article will be ejected into and through the tube,said tube being movable about a vertical axis to an operative positionover the mold and an inoperative position away from the mold in adirection opposite from the direction of movement of the transfer arm tothe oven.
 23. An apparatus according to claim 22, including means forinterconnecting the removal tube and the transfer arm for coordinatedmovement such that only one of them is located over the blow mold at anyone time.
 24. An apparatus according to claim 23, including a fixedvertical support tube near the blow mold, a horizontal arm connected tothe support tube and turnable about an axis, said arm locating the saidopen end of the tube, said interconnecting means being operable tointerrelate turning movement of the said horizontal arm and the saidtransfer arm about their respective vertical axes.
 25. An apparatus forproducing blow molded articles comprising: a base, a stationary ovenremovably connected to the base, said oven including a housing and meansfor moving tubular parisons through the oven from a loading station to adischarge station, a blow mold removably mounted on the base at aboutthe same height as the oven and adjacent the oven and including a meansfor supporting a tubular parison and forming it into a molded article, atransfer member for transferring heated tubular parisons from the ovento the mold, said transfer member comprising a vertical spindle movableabout and vertically along a vertical axis, a horizontal transfer armattached to the spindle and movable therewith vertically along andangularly about said axis, a gripping means attached to the transfer armfor movement therewith and extending downwardly therefrom for grippingthe top of a tubular parison, said transfer member being removablyconnected to the base with the said spindle located generally betweenthe oven and the mold and generally equidistant in a horizontal linefrom the oven discharge station and from the center of the mold, saidblow mold and said transfer arm being of modular construction andcapable of being removed each independently of the other.
 26. Anapparatus according to claim 25, wherein the oven is elongated, and saidtransfer member and saiD blow mold are connected to the base adjacentone end of the oven, said mold comprising mold halves movable towardsand away from each other in a generally horizontal direction.
 27. Anapparatus according to claim 26, including a thread clamp means locatedon the base beneath the mold means for holding and forming the openingin the bottom of the parison and wherein said thread clamp means is alsoremovable from the base independently from the other said means.
 28. Anapparatus according to claim 27, including a feeding means removablymounted above the oven for receiving parisons and delivering the sameinto the oven.
 29. An apparatus for blow molding articles comprising: anoven including means for passing elongated tubular parisons through theoven to heat the parisons along their entire lengths, a blow mold, atransfer means for taking the heated parisons from the oven to the blowmold, and stretching means for stretching each elongated parisonlongitudinally while it is at the blow mold just before the parison ismolded into a finished article, said stretching means including thetransfer means which holds one end of the parison during stretching. 30.An apparatus according to claim 29 including support means at the blowmold for holding one end of the parison, said transfer means beingoperable to pull the other end of the parison while the support meanshold the said one end thereof, to thereby stretch the parison.
 31. Anapparatus according to claim 30, said support means being operable tohold the bottom of the parison in the position which the parison willassume during blow molding, and said transfer means being operable tograsp the top of the parison and urge it upwardly to stretch the parisonwhile the support means holds the bottom thereof.
 32. An apparatusaccording to claim 29, said oven including means for passing theparisons therethrough in an upright position, said transfer means beinga transfer arm which includes a gripping means for lifting a parisonupwardly out of the oven, transferring the parison horizontally to theblow mold and lowering the parison at the blow mold onto the supportmeans.
 33. An apparatus according to claim 32, said transfer arm beingrotatable about a vertical axis between the oven and the blow mold. 34.An apparatus according to claim 33, said transfer arm being movablevertically along its axis to grip the parison at the oven and releasethe parison at the mold station.
 35. An apparatus according to claim 29including support means at the blow mold for holding the end of theparison through which air is to be blown during the blow molding, saidtransfer means being operable to grasp the other end of the parison topull the same to stretch the parison.
 36. An apparatus according toclaim 35, the end of the parison held by the support means being thebottom end, and means for passing air through the support means into theparison during blow molding.
 37. An apparatus for blow molding articlescomprising: an oven including a parison loading station and a parisondischarge station, continuously operable conveying means for conveyingparisons through the oven to heat the same, a blow mold, a transfermeans including parison hodling means for taking hold of parisons at thedischarge station of the oven, removing the parisons from thecontinuously operable conveying means in the oven and transferring theparisons to the blow mold, and means for effecting essentially zerorelative movement between the said holding means and the conveying meansin the direction of movement of the conveying means at the dischargestation while the conveying means continues to operate continuously,whereby the transfer means is operable to successively remove parisonsat the discharge station without stopping the continuous operation ofthe conveying means.
 38. An apparatus according to claim 37, saidconveying means being an endless conveyor within the oven which includesmeans for supporting elongated parisons in aN upright position, saidtransfer means holding means being movable vertically down into the ovento take hold of a parison, movable generally horizontally with theconveying means as it takes hold of a parison, and upwardly out of theoven to remove the parison from the oven.
 39. An apparatus according toclaim 38, said transfer means being a transfer arm including the holdingmeans thereon, the transfer arm being rotatable about a vertical axis.40. An apparatus according to claim 39, wherein said transfer arm ismovable about said vertical axis in timed relationship with theconveying means as the holding means takes hold of the parison to effectsaid zero relative movement.
 41. An apparatus according to claim 40,said transfer means being movable vertically to raise the parison fromthe oven, horizontally about said axis to transfer the parison to theblow mold, and movable vertically at the blow mold to lower the parisonto the blow mold.